Agriculture is a major source of NO
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            pollution in California

Almaraz, Maya; Bai, Edith; Chao, Wang; Trousdell, Justin; Conley, Stephen; Faloona, I. C.; Houlton, Benjamin Z.

doi:10.1126/sciadv.aao3477

Cited by 171 publications

(132 citation statements)

References 47 publications

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“…Most previous research has focused on urban air pollution, but rural areas should be considered in studies of air quality and its effects. In the current study, the focus was on coal mining and burning as a potential source of rural air pollution, but other contributing factors may be present as well in specific rural environments such as agriculture, 45 animal husbandry, 46 or mining for other products besides coal. 47 There are many arguments to be made for transitioning from coal to alternative methods of metal production 48 and energy generation.…”

Section: Discussionmentioning

confidence: 99%

Air Quality in Association With Rural Coal Mining and Combustion in New South Wales Australia

Hendryx

Higginbotham

Ewald

et al. 2019

The Journal of Rural Health

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Purpose Rural areas may face under‐recognized threats to air quality. We tested 2 hypotheses that 1) rural areas in New South Wales, Australia, would have better air quality than metropolitan Sydney, and that 2) the rural Upper Hunter region characterized by coal mining and coal combustion would have worse air quality than other rural areas of the state. Methods We analyzed 2017 daily mean values for New South Wales, Australia, for particulate matter (PM2.5 and PM10), sulfur dioxide (SO2), nitric oxide (NO), nitrogen dioxide (NO2), and NOx (sum of NO and NO2). Forty‐six air monitoring stations were grouped into 6 rural and urban regional areas. Linear regression models examined pollution levels in association with rural and urban regions and meteorological covariates. Results Findings show that daily mean pollutant levels in the rural Upper Hunter were the highest of all regions, and were significantly higher than metropolitan Sydney, with and without control for weather conditions, for every pollutant. For example, daily mean PM2.5 was 8.64 µg/m3 in the rural Upper Hunter, compared to 7.23 µg/m3 in metropolitan Sydney. Conclusions Results highlight the need to consider both urban and rural sources of pollution in air quality studies, and appropriate policy steps to address likely rural air pollution from coal mining.

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Section: Discussionmentioning

confidence: 99%

Air Quality in Association With Rural Coal Mining and Combustion in New South Wales Australia

Hendryx

Higginbotham

Ewald

et al. 2019

The Journal of Rural Health

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“…The most recent inventory shows that U.S. anthropogenic NO x emissions decreased by 49% from 2000-2014 (Hoesly et al, 2018). It should be noted that fertilized agricultural and soil emissions of NO x may be substantial, and may become more important as industrial emissions decline (Jaeglé et al, 2005;Almaraz et al, 2018). These emissions have higher uncertainties than the industrial emissions.…”

Section: Interannual Variability and Trends In Baseline And Usb Omentioning

confidence: 99%

Scientific assessment of background ozone over the U.S.: Implications for air quality management

Jaffe

Cooper

Fiore

et al. 2018

Elementa: Science of the Anthropocene

107

149

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Ozone (O3) is a key air pollutant that is produced from precursor emissions and has adverse impacts on human health and ecosystems. In the U.S., the Clean Air Act (CAA) regulates O3levels to protect public health and welfare, but unraveling the origins of surface O3is complicated by the presence of contributions from multiple sources including background sources like stratospheric transport, wildfires, biogenic precursors, and international anthropogenic pollution, in addition to U.S. anthropogenic sources. In this report, we consider more than 100 published studies and assess current knowledge on the spatial and temporal distribution, trends, and sources of background O3over the continental U.S., and evaluate how it influences attainment of the air quality standards. We conclude that spring and summer seasonal mean U.S. background O3(USB O3), or O3formed from natural sources plus anthropogenic sources in countries outside the U.S., is greatest at high elevation locations in the western U.S., with monthly mean maximum daily 8-hour average (MDA8) mole fractions approaching 50 parts per billion (ppb) and annual 4thhighest MDA8s exceeding 60 ppb, at some locations. At lower elevation sites, e.g., along the West and East Coasts, seasonal mean MDA8 USB O3is in the range of 20–40 ppb, with generally smaller contributions on the highest O3days. The uncertainty in U.S. background O3is around ±10 ppb for seasonal mean values and higher for individual days. Noncontrollable O3sources, such as stratospheric intrusions or precursors from wildfires, can make significant contributions to O3on some days, but it is challenging to quantify accurately these contributions. We recommend enhanced routine observations, focused field studies, process-oriented modeling studies, and greater emphasis on the complex photochemistry in smoke plumes as key steps to reduce the uncertainty associated with background O3in the U.S.

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“…For the nitrate model, top ranking variables included population and impervious surface, which are both related to anthropogenic fossil fuel combustion that could release NO x , precursor gases of nitrate. Shrub cover, which reflects the emission sources of soil NO x [36,37], also ranked high. Variables of high importance rankings were similar for OC and EC, which were mostly land use variables that could represent the spatial patterns of local-scale emissions sources.…”

Section: Model Evaluationmentioning

confidence: 99%

Random forest models for PM_2.5 speciation concentrations using MISR fractional AODs

Geng

Meng

et al. 2020

Environ. Res. Lett.

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It is increasingly recognized that various chemical components of PM 2.5 might have differential toxicities to human health, although such studies are hindered by the sparse or non-existent coverage of ground PM 2.5 speciation monitors. The Multi-angle Imaging SpectroRadiometer (MISR) onboard the Terra satellite has an innovative design to provide information about aerosol shape, size and extinction that are more related to PM 2.5 speciation concentrations. In this study, we developed random forest models that incorporated ground measurements of PM 2.5 species, MISR fractional AODs, simulated PM 2.5 speciation concentrations from a chemical transport model (CTM), land use variables and meteorological fields, to predict ground-level daily PM 2.5 sulfate, nitrate, organic carbon (OC) and elemental carbon (EC) concentrations in California between 2005 and 2014. Our models had out-of-bag R 2 of 0.72, 0.70, 0.68 and 0.70 for sulfate, nitrate, OC and EC, respectively. We also conducted sensitivity tests to explore the influence of variable selection on model performance. Results show that if there are sufficient ground measurements and predictor data to support the most sophisticated model structure, fractional AODs and total AOD have similar predicting power in estimating PM 2.5 species. Otherwise, models using fractional AODs outperform those with total AOD. PM 2.5 speciation concentrations are more sensitive to land use variables than other supporting data (e.g., CTM simulations and meteorological information).

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Agriculture is a major source of NO _x pollution in California

Abstract: Agriculturally fertilized soil is a dominant source of NOx pollution in California.

Cited by 171 publications

References 47 publications

Air Quality in Association With Rural Coal Mining and Combustion in New South Wales Australia

Air Quality in Association With Rural Coal Mining and Combustion in New South Wales Australia

Scientific assessment of background ozone over the U.S.: Implications for air quality management

Random forest models for PM_2.5 speciation concentrations using MISR fractional AODs

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Agriculture is a major source of NO x pollution in California

Abstract: Agriculturally fertilized soil is a dominant source of NOx pollution in California.

Cited by 171 publications

References 47 publications

Air Quality in Association With Rural Coal Mining and Combustion in New South Wales Australia

Air Quality in Association With Rural Coal Mining and Combustion in New South Wales Australia

Scientific assessment of background ozone over the U.S.: Implications for air quality management

Random forest models for PM2.5 speciation concentrations using MISR fractional AODs

Contact Info

Product

Resources

About

Agriculture is a major source of NO _x pollution in California

Random forest models for PM_2.5 speciation concentrations using MISR fractional AODs