Pediatric asthma, photochemical oxidant air pollutants, and climate change vulner

描述（由申请人提供）：随着全球变暖，预计臭氧（O3）等光化学氧化空气污染物将增加。鉴于已知的臭氧影响，预计这将对哮喘儿童的健康产生重大影响。然而，关于二次有机气溶胶（SOA）中光化学氧化污染物的重要性的信息要少得多，它们在许多方面可能比环境中的臭氧对呼吸系统健康造成更大的危害。因此，仅使用O3可能会低估全球变暖导致的光化学空气污染物增加对易感人群哮喘发病率的潜在影响。弱势群体可能包括有色人种儿童和社会经济地位较低的儿童。易受伤害的人群还包括那些生活在交通繁忙地区、化石燃料燃烧初级产物（包括SOA前体）浓度较高的人群，或者生活在这些来源地点顺风处、温度较高地区、光化学老化的城市气溶胶（包括SOA）浓度较高的人群。我们假设儿童每日哮喘发病率将与局部暴露于光化学氧化空气污染物的增加有关，而与主要燃烧相关的空气污染物的影响无关。此外，我们假设这些关联在生活在社会经济地位较低地区和光化学空气污染较多的温暖地区的受试者中会更强。我们预计，这种哮喘的风险将随着未来气候和潜在排放清单的变化而增加，这些变化共同决定了污染物浓度。我们将使用四个目标来解决这些假设：我们将首先估计2000-2008年整个加利福尼亚州邮政编码级别的每日空气污染物暴露。空气污染物将包括环境测量环境保护局规定的标准空气污染物。我们还将采用一个面向源的化学运输模型来估计邮政编码对O3、NO2、粒径分异颗粒种类（包括SOA和主要污染物）和颗粒源的特定暴露。然后，我们将评估局部暴露于光化学氧化剂（SOA和O3）以及其他污染物的儿童因哮喘就诊和住院的风险。随后将评估可能增加脆弱性的学科和地理因素对关联的影响改变。最后，我们将评估全球变暖对光化学污染物水平的影响对儿童哮喘发病率的潜在未来风险，并根据假设的人群脆弱性进行分层。拟议的研究将最先进的反应化学传输模型与最新的SOA形成理论相结合，并将其应用于与气候相关的分析阶段，以确定未来SOA浓度是否会因气候变化而发生重大变化。了解这一点对于充分评估气候变化对易受光化学氧化空气污染健康影响的特定人群的影响至关重要。

DESCRIPTION (provided by applicant): Photochemical oxidant air pollutants such as ozone (O3) are anticipated to increase with global warming. Given the known effects of O3, this is anticipated to have major impacts on the health of children with asthma. However, there is much less information about the importance of the photochemical oxidant pollutants in secondary organic aerosols (SOA), which in many respects have the potential to do greater harm to respiratory health than ambient O3. Therefore, the potential impact on asthma morbidity among vulnerable populations from photochemical air pollutant increases resulting from global warming is likely to be underestimated using O3 alone. Vulnerable populations may include children of color and those with low socioeconomic status. Vulnerable people also include those living in heavily trafficked regions with higher concentrations of primary products of fossil fuel combustion (which include SOA precursors), or people living downwind of these source sites in hotter regions with high concentrations of photochemically aged urban aerosols including SOA. We hypothesize that daily asthma morbidity in children will be associated with increased local exposures to photochemical oxidant air pollutants, independent of the effects of primary combustion-related air pollutants. Furthermore, we hypothesize that these associations will be stronger in subjects living in regions with lower socioeconomic status and in warmer regions with more photochemical air pollution. We anticipate that such risks of asthma will increase with future changes to climate and to the underlying emissions inventory that together determine pollutant concentrations. Four aims will be used to address these hypotheses: We will first estimate daily air pollutant exposures at the zip code level throughout the state of California for 2000-2008. Air pollutants will include ambient measurements of EPA-regulated criteria air pollutants. We will also employ a source-oriented chemical transport model to estimate zip-code specific exposures to O3, NO2, size-fractionated particle species (including SOA and primary pollutants) and particle sources. We will then assess the risk of emergency department visits and hospital admissions for asthma among children from local exposures to photochemical oxidants (SOA and O3), among other pollutants. This will be followed by an assessment of effect modification of associations by subject and geographic factors that may represent increased vulnerability. Finally, we will assess the potential future risk of pediatric asthma morbidity from the effects of global warming on photochemical pollutant levels, stratified by hypothesized population vulnerabilities. The proposed research combines a state-of-the-science reactive chemical transport model with the latest SOA formation theories and applies them over climatologically relevant analysis periods to determine if SOA concentrations will experience significant changes in the future due to climate modification. Knowing this is critical to fully assessing the impact of climate change on specific populations vulnerable to the health effects of photochemical oxidant air pollution. PUBLIC HEALTH RELEVANCE: The knowledge that will emerge from the proposed study will be of benefit to public health by identifying populations of children with asthma who are most vulnerable to the adverse effects of photochemical and other air pollutants that are expected to increase with global warming. We will estimate the potential magnitude of increased asthma morbidity that could result from future changes to climate and to the underlying emissions inventory that together determine pollutant concentrations. These estimated effects are anticipated to be larger among children of color, and those living in poverty or in warmer regions downwind of major urban sources of air pollutants from fossil fuel combustion.