Urban form and air quality in the United States

AbstractSeasonal influenza is a recurring health burden shared widely across the globe. We study whether air quality affects the occurrence of severe influenza cases that require inpatient hospitalization. Using longitudinal information on local air quality and hospital admissions across the United States, we find that poor air quality increases the incidence of significant influenza hospital admissions. Effects diminish in years with greater influenza vaccine effectiveness. Apart from increasing vaccination rates, improving air quality may help reduce the spread and severity of influenza.

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Model analyses of atmospheric mercury: present air quality and effects of transpacific transport on the United States

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-9849-2013 ◽

2013 ◽

Vol 13 (4) ◽

pp. 9849-9893 ◽

Cited By ~ 2

Author(s):

H. Lei ◽

X.-Z. Liang ◽

D. J. Wuebbles ◽

Z. Tao

Keyword(s):

United States ◽

Air Quality ◽

Wet Deposition ◽

Total Mercury ◽

The United States ◽

Atmospheric Mercury ◽

Anthropogenic Sources ◽

Mercury Deposition ◽

Transpacific Transport ◽

Mercury Cycle

Abstract. Atmospheric mercury is a toxic air and water pollutant that is of significant concern because of its effects on human health and ecosystems. A mechanistic representation of the atmospheric mercury cycle is developed for the state-of-the-art global climate-chemistry model, CAM-Chem (Community Atmospheric Model with Chemistry). The model simulates the emission, transport, transformation and deposition of atmospheric mercury (Hg) in three forms: elemental mercury (Hg(0)), reactive mercury (Hg(II)), and particulate mercury (PHg). Emissions of mercury include those from human, land, ocean, biomass burning and volcano related sources. Land emissions are calculated based on surface solar radiation flux and skin temperature. A simplified air–sea mercury exchange scheme is used to calculate emissions from the oceans. The chemistry mechanism includes the oxidation of Hg(0) in gaseous phase by ozone with temperature dependence, OH, H2O2 and chlorine. Aqueous chemistry includes both oxidation and reduction of Hg(0). Transport and deposition of mercury species are calculated through adapting the original formulations in CAM-Chem. The CAM-Chem model with mercury is driven by present meteorology to simulate the present mercury air quality during the 1999–2001 periods. The resulting surface concentrations of total gaseous mercury (TGM) are then compared with the observations from worldwide sites. Simulated wet depositions of mercury over the continental United States are compared to the observations from 26 Mercury Deposition Network stations to test the wet deposition simulations. The evaluations of gaseous concentrations and wet deposition confirm a strong capability for the CAM-Chem mercury mechanism to simulate the atmospheric mercury cycle. The results also indicate that mercury pollution in East Asia and Southern Africa is very significant with TGM concentrations above 3.0 ng m−3. The comparison to wet deposition indicates that wet deposition patterns of mercury are more affected by the spatial variability of precipitation. The sensitivity experiments show that 22% of total mercury deposition and 25% of TGM concentrations in the United States are resulted from domestic anthropogenic sources, but only 9% of total mercury deposition and 7% of TGM concentrations are contributed by transpacific transport. However, the contributions of domestic and transpacific sources on the western United States levels of mercury are of comparable magnitude.

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Air Quality and Power Production in the United States: Emissions Trading and State-Level Initiatives in the Control of Acid-Producing Emissions, Mercury, and Carbon Dioxide

Acid in the Environment ◽

10.1007/978-0-387-37562-5_10 ◽

2007 ◽

pp. 203-221 ◽

Cited By ~ 1

Author(s):

Daniel Sosland

Keyword(s):

United States ◽

Carbon Dioxide ◽

Air Quality ◽

Emissions Trading ◽

State Level ◽

Power Production ◽

The United States

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RE: “EPIDEMIOLOGIC EVIDENCE AND THE UNITED STATES AIR QUALITY STANDARDS”

American Journal of Epidemiology ◽

10.1093/oxfordjournals.aje.a112922 ◽

1980 ◽

Vol 111 (4) ◽

pp. 458-459 ◽

Cited By ~ 4

Author(s):

W. W. Holland ◽

A. E. Bennett ◽

I. R. Cameron ◽

C. du V. Florey ◽

S. R. Leeder ◽

...

Keyword(s):

United States ◽

Air Quality ◽

Quality Standards ◽

The United States ◽

Air Quality Standards ◽

Epidemiologic Evidence

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Fingerprints of a New Normal Urban Air Quality in S5P TROPOMI Tropospheric NO2 Observations

10.5194/egusphere-egu21-16363 ◽

2021 ◽

Author(s):

Shobha Kondragunta

Keyword(s):

United States ◽

Air Quality ◽

Unemployment Rate ◽

Power Plants ◽

The United States ◽

Urban Air Quality ◽

Urban Air ◽

Nox Emissions ◽

Percentage Increase ◽

New Normal

Most countries around the world took actions to control COVID-19 spread that included social distancing, limiting air and ground travel, closing schools, suspending sports leagues, closing factories etc., leading to&#160; economic shutdown. The reduced traffic and human movement compared to Business as Usual (BAU) scenario was tracked by Apple and Android cellphone use; the data showed substantial reductions in mobility in most metropolitan areas.&#160; We analyzed reductions in on-road mobile NOx emissions from light and heavy duty vehicles in four major metropolitan and one rural areas in the United States that showed a reduction in NOx mobile emissions from 9% to 19% between February and March at the onset of lockdown in the middle of March; between March and April, the mobile NOx emissions dropped further by 8% to 31% when lockdown measures were the most stringiest.&#160; These precipitous drops in NOx emissions correlated well with tropospheric NO2 column amount observed by Sentinel 5 Precursor TROPospheric Ozone Monitoring Instrument (S5P TROPOMI).&#160; Further, the changes in TROPOMI tropospheric NO2 across the continental U.S. between 2020 and 2019 correlated well with changes in on-road NOx emissions (r=0.78) but correlated weakly with changes in emissions from the power plants (r=0.44). These findings confirm that power plants are no longer the major source of NO2 in the United States. We also examined correlation between increase in unemployment rate between 2020 and 2019 to decrease in tropospheric NO2 amount.&#160; The negative correlation indicates that with increased unemployment rate combined with telework policies across the nation for non-essential workers, the NO2 values decreased at the rate of 0.8 &#181;moles/m2 decrease per unit percentage increase in unemployment rate.&#160; There is a substantial amount of scatter in the data with some cities such as Atlanta, Dallas, and Houston showing no noticeable trend in tropospheric NO2 changes during the time period when unemployment rate increased from 6% to 12%.&#160;&#160; We examined the trends in on-road and power plant emissions for five different locations (four urban areas and one rural area) and show that the changes in NOx emissions during the lockdown are detectable in TROPOMI tropNO2 data, the economic indicators are consistent with emissions changes, and the trends reversing with the removal of lockdown measures in the major metro areas have not come back to pre-pandemic levels.&#160; The COVID-19 pandemic experience has provided the scientific community an opportunity to identify emissions reductions scenarios that created a new normal for urban air quality and if the environmental protection agencies should look at this new normal as a guidance for instituting new policies.&#160;

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