scholarly journals Importance of Meteorology and Chemistry in Determining Air Pollutant Levels During COVID-19 Lockdown in Indian Cities

2021 ◽  
Author(s):  
Leigh Crilley ◽  
Yashar Iranpour ◽  
Cora J. Young
Keyword(s):  
Atmospheric Chemistry ◽  
Field Measurements ◽  
Air Pollutant ◽  
Mitigation Strategies ◽  
Ozone Production ◽  
Linear Relationships ◽  
Regional Sources ◽  
Volatile Organic ◽  
Emission Changes ◽  
Indian Cities

To accurately quantify impact of short-term interventions (such as COVID-19 lockdown) on air pollutant levels, meteorology and atmospheric chemistry need to be considered in addition to emission changes. We demonstrate that regional sources have a significant influence on PM<sub>2.5 </sub>levels in Delhi and Hyderabad due to the small reduction calculated post-lockdown after weather-normalization, indicating that future PM<sub>2.5</sub> mitigation strategies should focus on national-scale, as well as local sources. Furthermore, we demonstrate with field measurements that ozone production in Delhi is likely volatile organic compound (VOC)-limited, in agreement with previous modelling predictions, indicating that ozone mitigation should focus on dominant VOC sources. This work highlights the complexity in developing mitigation strategies for air pollution due to its non-linear relationships with emissions, chemistry and meteorology.

scholarly journals Importance of Meteorology and Chemistry in Determining Air Pollutant Levels During COVID-19 Lockdown in Indian Cities

2021 ◽  
Author(s):  
Leigh Crilley ◽  
Yashar Iranpour ◽  
Cora J. Young
Keyword(s):  
Atmospheric Chemistry ◽  
Field Measurements ◽  
Air Pollutant ◽  
Mitigation Strategies ◽  
Ozone Production ◽  
Linear Relationships ◽  
Regional Sources ◽  
Volatile Organic ◽  
Emission Changes ◽  
Indian Cities

To accurately quantify impact of short-term interventions (such as COVID-19 lockdown) on air pollutant levels, meteorology and atmospheric chemistry need to be considered in addition to emission changes. We demonstrate that regional sources have a significant influence on PM<sub>2.5 </sub>levels in Delhi and Hyderabad due to the small reduction calculated post-lockdown after weather-normalization, indicating that future PM<sub>2.5</sub> mitigation strategies should focus on national-scale, as well as local sources. Furthermore, we demonstrate with field measurements that ozone production in Delhi is likely volatile organic compound (VOC)-limited, in agreement with previous modelling predictions, indicating that ozone mitigation should focus on dominant VOC sources. This work highlights the complexity in developing mitigation strategies for air pollution due to its non-linear relationships with emissions, chemistry and meteorology.

Unexpected Fast Monoterpene Oxidation In Eastern China

2021 ◽  
Author(s):  
Haichao Wang
Keyword(s):  
Eastern China ◽  
Field Measurements ◽  
Ozone Production ◽  
Nitrate Radical ◽  
Peroxy Radicals ◽  
Ozone Pollution ◽  
Volatile Organic ◽  
Secondary Aerosols ◽  
Photochemical Ozone

&lt;p&gt;Monoterpene plays an important role in the formation of secondary aerosols and ozone in the troposphere. However, the field characterization of monoterpene chemistry in ozone pollution is still very sparse. Here we report fast daytime oxidation of monoterpene by hydroxyl radical, nitrate radical and ozone based on field measurements in Eastern China. We find fast monoterpene oxidation produces peroxy radicals efficiently and enhances the photochemical ozone production largely with an additional 8.6 ppb of ozone production per day on average (14%), whose effect was even more important than that of isoprene chemistry in the analyzed dataset. We propose that the reduction of anthropogenic volatile organic compounds should be much more stringent in the presence of high monoterpenes to alleviating ozone pollution.&lt;/p&gt;

scholarly journals Characterization of Volatile Organic Compound (VOC) Emissions from Swine Manure Biogas Digestate Storage

Atmosphere ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 411 ◽  
Author(s):  
Yu Zhang ◽  
Zhiping Zhu ◽  
Yunhao Zheng ◽  
Yongxing Chen ◽  
Fubin Yin ◽  
...  
Keyword(s):  
Organic Compound ◽  
Volatile Organic Compound ◽  
Total Concentration ◽  
Swine Manure ◽  
Air Pollutant ◽  
Mitigation Strategies ◽  
Halogenated Hydrocarbons ◽  
Voc Emissions ◽  
Volatile Organic ◽  
Biogas Digestate

Livestock manure is one of the major sources of volatile organic compound (VOC) emissions; however, characteristics of VOCs emitted from biogas digestate (BD) storage, which is a common manure practice, remain unclear. The objective of this study was to characterize VOC emissions during BD storage through the dynamic emission vessel method, to identify the VOC emissions that have potential odor and/or toxic effects. The results revealed the detection of 49 VOCs with seven classes, whose total concentration varied from 171.35 to 523.71 μg m−3. The key classes of the 49 VOCs included Oxygenated VOCs (OVOCs), olefins and halogenated hydrocarbons. The top four compositions, accounting for 74.38% of total VOCs (TVOCs), included ethanol, propylene, acetone and 2-butanone. The top four odorous VOCs, accounting for only 5.15% of the TVOCs, were toluene, carbon disulfide, ethyl acetate and methyl sulfide, with the concentration ranging from 13.25 to 18.06 μg m−3. Finally, 11 main hazardous air pollutant VOCs, accounting for 32.77% of the TVOCs, were propylene, 2-butanone, toluene, methyl methacrylate, etc., with the concentration ranging from 81.05 to 116.96 μg m−3. Results could contribute to filling the knowledge gaps in the characteristics of VOC emissions from biogas digestate (BD), and provide a basis for exploring mitigation strategies on odor and hazardous air pollutions.

scholarly journals Unexplored volatile organic compound emitted from petrochemical facilities: implications for ozone production and atmospheric chemistry

2021 ◽  
Vol 21 (15) ◽  
pp. 11505-11518
Author(s):  
Chinmoy Sarkar ◽  
Gracie Wong ◽  
Anne Mielnik ◽  
Sanjeevi Nagalingam ◽  
Nicole Jenna Gross ◽  
...  
Keyword(s):  
Organic Compound ◽  
Volatile Organic Compound ◽  
Atmospheric Chemistry ◽  
Proton Transfer Reaction ◽  
Ozone Production ◽  
Emission Rates ◽  
Mixing Ratios ◽  
Volatile Organic ◽  
Calculated Average ◽  
Tof Ms

Abstract. A compound was observed using airborne proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS) measurements in the emission plumes from the Daesan petrochemical facility in South Korea. The compound was detected at m/z 43.018 on the PTR-TOF-MS and was tentatively identified as ketene, a rarely measured reactive volatile organic compound (VOC). Estimated ketene mixing ratios as high as ∼ 50 ppb (parts per billion) were observed in the emission plumes. Emission rates of ketene from the facility were estimated using a horizontal advective flux approach and ranged from 84–316 kg h−1. These emission rates were compared to the emission rates of major known VOCs such as benzene, toluene, and acetaldehyde. Significant correlations (r2 > 0.7) of ketene with methanol, acetaldehyde, benzene, and toluene were observed for the peak emissions, indicating commonality of emission sources. The calculated average ketene OH reactivity for the emission plumes over Daesan ranged from 3.33–7.75 s−1, indicating the importance of the quantification of ketene to address missing OH reactivity in the polluted environment. The calculated average O3 production potential for ketene ranged from 2.98–6.91 ppb h−1. Our study suggests that ketene, or any possible VOC species detected at m/z 43.018, has the potential to significantly influence local photochemistry, and therefore, further studies focusing on the photooxidation and atmospheric fate of ketene through chamber studies are required to improve our current understanding of VOC OH reactivity and, hence, tropospheric O3 production.

scholarly journals Higher measured than modeled ozone production at increased NO<sub><i>x</i></sub> levels in the Colorado Front Range

2017 ◽  
Author(s):  
Bianca Baier ◽  
William Brune ◽  
David Miller ◽  
Donald Blake ◽  
Russell Long ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Mitigation Strategies ◽  
Peroxyl Radicals ◽  
Chemical Mechanism ◽  
Colorado Front Range ◽  
Ozone Production ◽  
Front Range ◽  
Volatile Organic

Abstract. Chemical models must accurately calculate the ozone formation rate, P(O3), to accurately predict ozone levels and test mitigation strategies. However, model chemical mechanisms can contain large uncertainties in P(O3) calculations, which can create uncertainties in ozone forecasts especially during the summertime when P(O3) can be high. One way to test mechanisms is to evaluate model P(O3) using direct measurements. During summer 2014, the Measurement of Ozone Production Sensor (MOPS) measured net P(O3) in Golden, CO, approximately 25 km west of Denver along the Colorado Front Range. Net P(O3) was compared to rates calculated by a photochemical box model using a lumped and a more explicit chemical mechanism. Observed P(O3) was up to a factor of two higher than that modeled during early morning hours when nitric oxide (NO) levels were high, contrary to traditional ozone chemistry theory. This disagreement may be due to model underestimation of hydroperoxyl (HO2) radicals relative to observations at high NO levels. These additional peroxyl radicals could come from the MOPS chamber chemistry or from missing volatile organic compounds co-emitted with NOx; additional cycling of OH into HO2 through reactions involving nitric oxide provides an alternate explanation for higher measured than modeled P(O3). Although the MOPS measurements are new, comparisons of observed and modeled P(O3) in NO space show a similar behavior to other comparisons between P(O3) derived from measurements and modeled P(O3). These comparisons can have implications for the sensitivity of P(O3) to nitrogen oxides and volatile organic compounds during morning hours, and can possibly affect ozone reduction strategies for the region surrounding Golden, CO in addition to other urban and suburban areas that are in non-attainment with national ozone regulations.

scholarly journals A simple modeling approach to study the regional impact of a Mediterranean forest isoprene emission on anthropogenic plumes

2004 ◽  
Vol 4 (6) ◽  
pp. 7691-7724 ◽  
Author(s):  
J. Cortinovis ◽  
F. Solmon ◽  
D. Serça ◽  
C. Sarrat ◽  
R. Rosset
Keyword(s):  
Atmospheric Chemistry ◽  
Field Measurements ◽  
Mediterranean Ecosystems ◽  
Tropospheric Chemistry ◽  
Ozone Production ◽  
Transfer Model ◽  
Data Sets ◽  
Isoprene Emission ◽  
On Line ◽  
The Impact

Abstract. Research over the past year has outlined the importance of biogenic isoprene emission in tropospheric chemistry, and notably in the context of regional ozone photo-oxidant pollution. The first part of this article deals with the development of a simple isoprene emission scheme based upon the classical Guenther's algorithm coupled with a soil-vegetation-atmosphere transfer model. The resulting emission scheme is tested in a "stand-alone" version at the canopy scale. Experimental data sets coming from Boreal, Tropical, Temperate and Mediterranean ecosystems are used to estimate the robustness of the scheme over contrasted climatic and ecological conditions. Considering the simple hypothesis used, simulated isoprene fluxes are generally consistent with field measurements and the emission scheme is thus deemed suitable for regional application. Limitations of the model are outlined as well as further improvements. In the second part of the article, the emission scheme is used on line in the broader context of a meso-scale atmospheric chemistry scheme. Dynamically idealized simulations are carried out to study the chemical interactions of pollutant plumes with realistic isoprene emissions coming from a Mediterranean oak forest. Two chemical scenarios are considered with anthropogenic emissions, respectively representative of the Marseille (urban) and Martigues (industrial) French Mediterranean areas. For the Marseille scenario, the impact of biogenic emission on ozone production is larger when the forest is situated in a sub-urban configuration (i.e. downwind distance TOWN-FOREST <30 km) and decrease quite rapidly as the distance increases. For the Martigues scenario, the biogenic impact on the plume is detectable even at a longer TOWN-FOREST distance of 100 km. For both cases, the importance of the VOC/NOx ratio, which characterizes the aging of advected pollutant plumes over the day, is outlined. Finally, possible applications of this work for real-case studies are discussed.

scholarly journals <i>α</i>-Pinene Nitrates: synthesis, yields and atmospheric chemistry

2011 ◽  
Vol 11 (2) ◽  
pp. 6845-6874
Author(s):  
S. X. Ma ◽  
J. D. Rindelaub ◽  
K. M. McAvey ◽  
P. D. Gagare ◽  
B. A. Nault ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Organic Aerosol ◽  
Reaction Chamber ◽  
Oxidation Products ◽  
Ozone Production ◽  
Organic Nitrate ◽  
Peroxy Radicals ◽  
Nitrate Precursor ◽  
Volatile Organic ◽  
Major Oxidation

Abstract. The biogenic volatile organic compound α-pinene is one of the dominant monoterpenes emitted to the Earth's atmosphere at an estimated rate of ~50 Tg yr−1. Its atmospheric oxidation products in the presence of NO can lead to ozone production, as well as production of secondary organic aerosol (SOA). The major oxidation pathway of α-pinene is reaction with OH, which in the presence of NO can form either α-pinene nitrates or convert NO to NO2, which can photolyze to form ozone. In this work, we successfully synthesized four α-pinene hydroxy nitrates through three different routes, and have identified the 4 individual isomers in α-pinene/OH/NO reaction chamber experiments. From the experiments, we determined their individual production yields, estimated the total RONO2 yield, and calculated the relative branching ratios of the nitrate precursor peroxy radicals (RO2). The combined yield of the four α-pinene nitrates was found to be 13.0 (±0.7) % at atmospheric pressure and 296 K, and the total organic nitrate yield was estimated to be 0.19 (+0.10/−0.06). We also determined the OH rate constants for two of the isomers, and have calculated their overall atmospheric lifetimes, which range between 22 and 38 h.

scholarly journals <i>α</i>-Pinene nitrates: synthesis, yields and atmospheric chemistry

2011 ◽  
Vol 11 (13) ◽  
pp. 6337-6347 ◽  
Author(s):  
S. X. Ma ◽  
J. D. Rindelaub ◽  
K. M. McAvey ◽  
P. D. Gagare ◽  
B. A. Nault ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Organic Aerosol ◽  
Reaction Chamber ◽  
Oxidation Products ◽  
Ozone Production ◽  
Organic Nitrate ◽  
Peroxy Radicals ◽  
Nitrate Precursor ◽  
Volatile Organic ◽  
Major Oxidation

Abstract. The biogenic volatile organic compound α-pinene is one of the dominant monoterpenes emitted to the Earth's atmosphere at an estimated rate of ~50 Tg C yr−1. Its atmospheric oxidation products in the presence of NO can lead to ozone production, as well as production of secondary organic aerosol (SOA). The major oxidation pathway of α-pinene is reaction with OH, which in the presence of NO can form either α-pinene nitrates or convert NO to NO2, which can photolyze to form ozone. In this work, we successfully synthesized four α-pinene hydroxy nitrates through three different routes, and have identified these 4 individual isomers in α-pinene/OH/NO reaction chamber experiments. From the experiments, we determined their individual production yields, estimated the total RONO2 yield, and calculated the relative branching ratios of the nitrate precursor peroxy radicals (RO2). The combined yield of the four α-pinene nitrates was found to be 0.130 (±0.035) at atmospheric pressure and 296 K, and the total organic nitrate yield was estimated to be 0.19 (+0.10/−0.06). We also determined the OH rate constants for two of the isomers, and have calculated their overall atmospheric lifetimes, which range between 22 and 38 h.

scholarly journals Isoprene nitrates: preparation, separation, identification, yields, and atmospheric chemistry

2010 ◽  
Vol 10 (4) ◽  
pp. 10625-10651 ◽  
Author(s):  
A. L. Lockwood ◽  
P. B. Shepson ◽  
M. N. Fiddler ◽  
M. Alaghmand
Keyword(s):  
Atmospheric Chemistry ◽  
Atmospheric Pressure ◽  
Oxidation Products ◽  
Ozone Production ◽  
Organic Nitrates ◽  
Relative Importance ◽  
Experimental Knowledge ◽  
Volatile Organic ◽  
Isoprene Nitrates ◽  
The Individual

Abstract. Isoprene is an important atmospheric volatile organic compound involved in ozone production and NOx (NO+NO2) sequestration and transport. Isoprene reaction with OH in the presence of NO can form either isoprene nitrates or convert NO to NO2 which can photolyze to form ozone. While it has been shown that isoprene nitrate production can represent an important sink for NOx in forest impacted environments, there is little experimental knowledge of the relative importance of the individual isoprene nitrate isomers, each of which has a different fate and reactivity. In this work, we have identified the 8 individual isomers and determined their total and individual production yields. The overall yield of isoprene nitrates at atmospheric pressure and 295 K was found to be 0.070(+0.025/–0.015). Three isomers, the (4,3)-IN, (1,2)-IN and Z-(4,1)-IN represent 90% of the total IN yield. We also determined the ozone rate constants for three of the isomers, and have calculated their atmospheric lifetimes, which range from ~1–2 h, making their oxidation products likely more important as atmospheric organic nitrates and sinks for nitrogen.

scholarly journals Isoprene nitrates: preparation, separation, identification, yields, and atmospheric chemistry

2010 ◽  
Vol 10 (13) ◽  
pp. 6169-6178 ◽  
Author(s):  
A. L. Lockwood ◽  
P. B. Shepson ◽  
M. N. Fiddler ◽  
M. Alaghmand
Keyword(s):  
Atmospheric Chemistry ◽  
Atmospheric Pressure ◽  
Oxidation Products ◽  
Ozone Production ◽  
Organic Nitrates ◽  
Relative Importance ◽  
Experimental Knowledge ◽  
Volatile Organic ◽  
Isoprene Nitrates ◽  
The Individual

Abstract. Isoprene is an important atmospheric volatile organic compound involved in ozone production and NOx (NO+NO2) sequestration and transport. Isoprene reaction with OH in the presence of NO can form either isoprene hydroxy nitrates ("isoprene nitrates") or convert NO to NO2 which can photolyze to form ozone. While it has been shown that isoprene nitrate production can represent an important sink for NOx in forest impacted environments, there is little experimental knowledge of the relative importance of the individual isoprene nitrate isomers, each of which has a different fate and reactivity. In this work, we have identified the 8 individual isomers and determined their total and individual production yields. The overall yield of isoprene nitrates at atmospheric pressure and 295 K was found to be 0.070(+0.025/−0.015). Three isomers, representing nitrates resulting from OH addition to a terminal carbon, represent 90% of the total IN yield. We also determined the ozone rate constants for three of the isomers, and have calculated their atmospheric lifetimes, which range from ~1–2 h, making their oxidation products likely more important as atmospheric organic nitrates and sinks for nitrogen.

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