Spatio-temporal of surface ozone (O3) variations at urban and suburban sites in Sarawak region of Malaysia

Sarawak Region of Malaysia is currently experiencing a high demand for capital needs such as transformation forest to plantations, economic development, and improving transportation systems. Those land cover changes will increase primary pollutant emissions and trigger surface O3 formation. Surface O3 is a secondary pollutant and a significant greenhouse gas contributing to climate change and declining air quality. In this study, variations in surface O3 concentrations at urban and suburban sites in Sarawak were explored using the Malaysian Department of Environment data spanning a two-year cycle (2018-2019). The primary aim of this study is to ascertain the variation of surface O3 concentrations reported at four monitoring stations in Sarawak, namely Kuching (SQ1) (Urban), Sibu (SQ2) (Suburban), Bintulu (SQ3) (Suburban), and Miri (SQ4) (Suburban). The study also analysed the relationship between O3 distribution and nitrogen oxides (NO and NO2). The findings showed that O3 concentrations observed in the region during the study period were lower than the maximum permissible value of 100 ppbv suggested by the Malaysian Ambient Air Quality Standard (2020). SQ4 (Miri) at suburban sites recorded the highest average surface O3 concentrations with an hourly average and daily maximum O3 concentration of 15.7 and 89.5 ppbv, respectively. Temperatures, UV exposure, and wind speed all impact the concentration of surface O3 in Sarawak. In all stations, concentrations of O3 were inversely linked with NO, NO2, and relative humidity (RH). This research will assist the relevant agency in forecast, monitor, and mitigate the level of O3 in the ambient environment, especially in the Sarawak Region.

The Fires, Asian, and Stratospheric Transport-Las Vegas Ozone Study (FAST-LVOS)

The Fires, Asian, and Stratospheric Transport-Las Vegas Ozone Study (FAST-LVOS) was conducted in May and June of 2017 to study the transport of ozone (O3) to Clark County, Nevada, a marginal non-attainment area in the Southwestern U.S. (SWUS). This 6-week (20 May–30 June 2017) field campaign used lidar, ozonesonde, aircraft, and in-situ measurements in conjunction with a variety of models to characterize the distribution of O3 and related species above southern Nevada and neighbouring California, and to probe the influence of stratospheric intrusions, wildfires, and local, regional, and Asian pollution on surface O3 concentrations in Las Vegas and the surrounding area. In this paper, we describe the FAST-LVOS campaign and present case studies illustrating the influence of different transport processes on background O3 and air quality attainment in the SWUS. The measurements found elevated O3 layers above Las Vegas on more than 75 % (35 of 45) of the sample days, and show that entrainment of these layers contributed to mean 8-h average background O3 concentrations of 50–55 parts-per-billion by volume (ppbv) across southern Nevada. These background concentrations constitute 70–80 % of the current U.S. National Ambient Air Quality Standard (NAAQS) of 70 ppbv, and illustrate some of the challenges facing air quality managers tasked with O3 attainment in the SWUS during late spring and early summer. The companion paper by Zhang et al. (2020) describes the use of the AM4 and GEOS-Chem global models to estimate the impacts of transported O3 on surface air quality in the Southwestern U.S. and Intermountain West during the FAST-LVOS campaign.

Observed Relationship between Ozone and Temperature for Urban Nonattainment Areas in the United States

This study examined the observed relationship between ozone (O3) and temperature using data from 1995 to 2020 at 20 cities across the United States (U.S.) that exceed the O3 National Ambient Air Quality Standard (NAAQS). The median slope of the O3 versus temperature relationship decreased from 2.8 to 1.5 parts per billion per degrees Celsius (ppb °C−1) in the eastern U.S., 2.2 to 1.3 ppb °C−1 in the midwestern U.S., and 1.7 to 1.1 ppb °C−1 in the western U.S. O3 in the eastern and midwestern U.S. has become less correlated with temperature due to emission controls. In the western U.S., O3 concentrations have declined more slowly and the correlation between O3 and temperature has changed negligibly due to the effects of high background O3 and wildfire smoke. This implies that meeting the O3 NAAQS in the western U.S. will be more challenging compared with other parts of the country.

Model Estimates and In-situ Measurements of the Concentrations of Some Gaseous Pollutants in Some Selected Standard Kitchens in Makurdi-Nigeria

This work assessed and compared the concentrations of some gaseous pollutants in some selected standard kitchens in Makurdi-Nigeria using in-situ measurements and models estimates. Mean concentrations of CO, NO2 and SO2 were measured using Crowcon gasman meters in all the selected kitchens. The results obtained show that CO and NO2 concentrations were observed in all the selected kitchens in concentrations below the permissible limit of 20 ppm and 0.6 ppm respectively set by National Ambient Air Quality Standard and SO2 was not observed. The mean concentrations for model estimates were found to be slightly higher compared to that of in-situ measurement in all the study kitchens for both pollutants, which is an indication of the strength of the model estimate. Pearson product moment correlation coefficient (r) was also computed to be 0.99 and 0.36 for CO and NO2respectively. The correlation is very strong and positive for CO (r = 0.99) and is weak but also positive for NO2 (r = 0.37). This implies that the model estimates used in this work has 99 % validity estimating indoor concentrations of CO where in-situ measurements are not possible. However, the positive correlation between the in-situ measurements and models estimates indicate that both are positively related.

Characteristics of Locally Occurring High PM2.5 Concentration Episodes in a Small City in South Korea

In this study, the ionic and carbonaceous compounds in PM2.5 were analysed in the small residential city of Chuncheon, Korea. To identify the local sources that substantially influence PM2.5 concentrations, the samples were divided into two groups: samples with PM2.5 concentrations higher than those in the upwind metropolitan area (Seoul) and samples with lower PM2.5 concentrations. During the sampling period (December 2016–August 2018), the average PM2.5 was 23.2 μg m−3, which exceeds the annual national ambient air quality standard (15 μg m−3). When the PM2.5 concentrations were higher in Chuncheon than in Seoul, the organic carbon (OC) and elemental carbon (EC) concentrations increased the most among all the PM2.5 components measured in this study. This is attributable to secondary formation and biomass burning, because secondary OC was enhanced and water soluble OC was strongly correlated with K+, EC, and OC. A principal component analysis identified four factors contributing to PM2.5: fossil-fuel combustion, secondary inorganic and organic reactions in biomass burning plumes, crustal dust, and secondary NH4+ formation.

Winter Ozone Pollution in Utah’s Uinta Basin is Attenuating

High concentrations of ground-level ozone have been observed during wintertime in the Uinta Basin of western Utah, USA, beginning in 2010. We analyze existing ozone and ozone precursor concentration data from 38 sites over 11 winter seasons and conclude that there has been a statistically significant (p < 0.02) decline in ozone concentration over the previous decade. Daily exceedances of the National Ambient Air Quality Standard for ozone (70 ppb) have been trending downward at the rate of nearly four per year. Ozone and NOx concentrations have been trending downward at the rates of about 3 and 0.3 ppb per year, respectively. Concentrations of organics in 2018 were at about 30% of their values in 2012 or 2013. Several markers, annual ozone exceedance counts and median ozone and NOx concentrations, were at their largest values in the period 2010 to 2013 and have never recovered since then. We attribute the decline to (1) weakening global demand for oil and natural gas and (2) more stringent pollution regulations and controls, both of which have occurred over the previous decade. We also see evidence of ozone titration when snow cover is absent.

Modeled Air Pollution from In Situ Burning and Flaring of Oil and Gas Released Following the Deepwater Horizon Disaster

The GuLF STUDY, initiated by the National Institute of Environmental Health Sciences, is investigating the health effects among workers involved in the oil spill response and clean-up (OSRC) after the Deepwater Horizon (DWH) explosion in April 2010 in the Gulf of Mexico. Clean-up included in situ burning of oil on the water surface and flaring of gas and oil captured near the seabed and brought to the surface. We estimated emissions of PM2.5 and related pollutants resulting from these activities, as well as from engines of vessels working on the OSRC. PM2.5 emissions ranged from 30 to 1.33e6 kg per day and were generally uniform over time for the flares but highly episodic for the in situ burns. Hourly emissions from each source on every burn/flare day were used as inputs to the AERMOD model to develop average and maximum concentrations for 1-, 12-, and 24-h time periods. The highest predicted 24-h average concentrations sometimes exceeded 5000 µg m−3 in the first 500 m downwind of flaring and reached 71 µg m−3 within a kilometer of some in situ burns. Beyond 40 km from the DWH site, plumes appeared to be well mixed, and the predicted 24-h average concentrations from the flares and in situ burns were similar, usually below 10 µg m−3. Structured averaging of model output gave potential PM2.5 exposure estimates for OSRC workers located in various areas across the Gulf. Workers located nearest the wellhead (hot zone/source workers) were estimated to have a potential maximum 12-h exposure of 97 µg m−3 over the 2-month flaring period. The potential maximum 12-h exposure for workers who participated in in situ burns was estimated at 10 µg m−3 over the ~3-month burn period. The results suggest that burning of oil and gas during the DWH clean-up may have resulted in PM2.5 concentrations substantially above the U.S. National Ambient Air Quality Standard for PM2.5 (24-h average = 35 µg m−3). These results are being used to investigate possible adverse health effects in the GuLF STUDY epidemiologic analysis of PM2.5 exposures.

Assessment and evaluation of ambient PM2.5 in relation to its health effects in mineral-based coal-fired areas

Atmospheric PM2.5 pollution, has shown potential impact on the human health in general, thus it requires to look into the chemical characteristics of PM2.5 masses for designing effective policies to reduce health risks amongst public under exposure. The study carried out, here, has presented the ambient PM2.5 concentrations, concentrations of chemical components and associated health risks over rural and urban environments in the area of mineral based coal-fired industrial areas of central India for a period of one year (2015–16). Overall 260 PM2.5 samples, collected from rural, urban and industrial sites, were analyzed for various elements Al, As, Ca, Hg, Cr, Co, Cu, Fe, Mn, K, Cd, Mo, Ni, Pb, Se, Sb, Na, Mg, K, V and Zn, ions such as Na+, Mg2+, K+, Ca2+, F–, Cl–, NH4+, NO3–, SO42– and carbonaceous matter. The annual average PM2.5 mass concentrations were found to be ~2 to ~6 folds higher than the annual National Ambient Air Quality standard (40 µg m–3). Further this study also evaluates, carcinogenic and non-carcinogenic health risks associated with ambient PM2.5 exposures (via ingestion, inhalation and dermal). The elemental species that have shown non-carcinogenic risks for both children and adults of all three sites are: Co, Mn, Ni (rural), As, Cd, Cr, Mn, Ni, V (urban and industrial sites). Similarly, the excess carcinogenic risks, in total, from Cd, Co, Cr, Ni, Pb was found to be higher than acceptable limits (10–6 to 10–4).

APLIKASI ALAT UKUR PARTIKULAT DAN SUHU BERBASIS IOT

Human daily life depends on air, so air quality needs to be protected especially against pollution. Decreasing air quality due to dust pollution can result in ARI. Makes it easier to measure ambient air and air temperature using internet-based technology. Designing internet-based dust and temperature measuring devices using the gp2y1010au0f type dust sensor, and DHS11 sensor as a temperature sensor, amplifier circuit, NodemCU microcontroller, and LCD (Liquid Crystal Display). The measurement application is carried out at the location of the PT. Djabus Tunas Utama Ngoro Mojokerto East Java at 10 sampling points around the mixing tube. The measurement results show the concentration carried by ambient air quality standards when the engine stops, so it is safe for employees. When the machine is mixing and the machine is not mixing (ordinary conditions) the concentration of particulates and the temperature exceeds the ambient air quality standard, for that all employees are required to use PPE.