更清洁的汽车，更清洁的空气

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California has a long history of poor air quality resulting from transportation 污染 on its roads. 早在1966年, 该州的617888九五至尊娱乐, 地理位置, 大量的车辆导致加州启动了减少乘用车和卡车污染的监管行动. 由于监管方面的持续进展, 目前在售的新乘用车的空气污染物排放量远低于旧车辆.

Gasoline vehicles result in emissions that both directly and indirectly produce fine particulate matter, 定义为空气中小于2的颗粒.直径5微米. 简称PM_2.5, these particles are small enough to penetrate deeply into the lungs; some can even enter the bloodstream. 慢性暴露于PM_2.5 导致心血管疾病导致死亡率上升, 包括心脏病发作, 它与肺癌和其他不良影响有关. 妊娠期和儿童期长期接触也与肺功能发育减慢和哮喘的发展有关, 对健康的其他负面影响.

A Fraction of the Vehicles on California Roads, Older Cars and Trucks Pollute More Than Newer Ones

从2004年开始, 加州对乘用车实施了最新的低排放车辆(LEVII)尾气排放标准，要求大幅减少空气污染排放. 旧车辆(2004年以前)占该州乘用车的19%，行驶里程仅占12%, 然而，它们排放的氮氧化物污染物几乎是2004年及以后所有汽车排放总量的三倍. 汽车排放的氮氧化物占乘用车排放总量的73%，活性有机气体占64%(表1)。. 这些污染物可以在大气中反应形成有害的PM_2.5 污染.

Although older vehicles represent fewer than one-fifth of the cars on California roads, they produce more nitrogen oxides and reactive organics gas emissions than all newer vehicles combined.

旧车排放的有害空气污染分布不均

Using the InMAP air-quality model and data from the California Air Resources Board, 忧思617888九五至尊娱乐家联盟(UCS)和Greenlining研究所(Greenlining)估计了PM的形成和运输_2.5 使用旧乘用车(定义为1976年至2003年车型)和新乘用车(2004年至2021年车型)造成的污染.¹ 结合PM_2.5 污染物浓度与美国人口普查数据, we estimated the exposure of Californians to harmful air 污染 from older cars.

我们的分析表明PM_2.5 在加州，使用2004年以前的车辆的风险在种族和人口群体中分布不均. 所有暴露于PM最高的区域_2.5 from older vehicles are in the southern half of California and mainly in central Los Angeles. PM污染负担最重的社区_2.5 来自老旧车辆的家庭比例是全州平均水平的两倍多，与没有这些车辆造成空气污染的地区相比，低收入和中等收入家庭的比例更高.

在该州颗粒物暴露率最高的地区 _2.5 污染 from older vehicles, over half of households have an income of less than $60,000 a year. 在暴露最少的地区, 只有35%的家庭收入低于60美元,000元/年(图1). 平均而言，收入较高的家庭接触到的PM浓度较低_2.5 所有乘用车造成的污染. Higher-income households also experience significantly less exposure to 污染 from older vehicles.

We also found racial and ethnic disparities in the exposure to air 污染 from passenger vehicles. These disparities, too, are greater for 污染 from older vehicles than for the fleet as a whole. For all passenger cars and trucks, White people are exposed to 17 percent lower concentrations of PM_2.5 低于州平均水平, 而拉丁裔加州人的暴露浓度高出13%，黑人加州人的暴露浓度高出11%.²

只看旧车的污染情况, White Californians are on average exposed to 20 percent lower concentrations of PM _2.5 低于州平均水平. 拉丁裔加州人的暴露浓度要高出19%, 而加州黑人的暴露浓度则高出12%.

接触PM最多的社区_2.5 这是该州平均水平的两倍多，这里的黑人和拉丁裔人口比例远高于整个州. 在这些暴露率最高的地区, 67 percent of residents are 拉丁美洲人 and 8 percent are Black; the state as a whole is 40 percent 拉丁美洲人 and 5 percent Black. 与此形成鲜明对比的是, those same areas of highest exposure are only 13 percent White; the state is 36 percent White (Figure 2).

进一步, 加州人已经面临着来自所有来源的最严重污染，他们还面临着旧车辆排放的首当其冲. 增加接触PM _2.5 污染 from older vehicles correlates with a community's score on CalEnviroScreen 4.0, 一种筛选方法，有助于确定受到多种污染源不成比例负担的社区. CalEnviroScreen中得分最高(负担最重)的人口普查区的人.他们暴露在老旧车辆污染浓度的环境中，是得分最低的人口普查区的两倍.

估计旧车辆污染导致的过早死亡

评估PM对健康的影响_2.5 旧车辆造成的污染, 我们研究了考虑发动机启动时排放的两种情况, 蒸发排放, 和驾驶. 这些情景提供了加州估计过早死亡的范围. One scenario only considered cold-start emissions and assumed those happen where the vehicle is registered. The second scenario assumed that all tailpipe emissions happen where the vehicle is registered. We estimated that older-vehicle emissions led to between 97 and 421 premature deaths per year. The impacts were concentrated in Southern California, especially Los Angeles County.

农村地区旧车的比例更高

而南加州的城市地区拥有最多的老旧车辆(也暴露在由此产生的污染中), 农村地区旧车的比例较高. 例如, 在摩多克农村, 三一, Sierra县, 超过40%的车辆是2003年或更老的车型. 与此形成鲜明对比的是, 橙色, 旧金山, 和河滨县, 这些城市都更加城市化, 该州旧车的比例是最低的.³

建议:减少不公平污染暴露的政策

基于旧车对当地空气质量和公众健康的影响, 因此，加州的相关机构必须优先考虑淘汰和更换老旧车辆. 政策制定者还应确保项目提供直接的帮助, 为弱势和低收入社区提供可衡量和有意义的利益. 此外, 在制定新政策和项目时, California should involve---and in meaningful ways---the communities most impacted by older-vehicle emissions. 这将有助于该州找到减少旧乘用车污染不公平分配的方法.

UCS and Greenlining recommend the following changes in state policies and programs:

• 优先向拥有旧车的重点人群提供奖励. State agencies should integrate programmatic changes to existing incentive programs, 比如清洁汽车4和清洁汽车援助计划, to prioritize investments in low-income and disadvantaged communities with high concentrations of older cars.

• Engage in intentional, targeted outreach and education to areas with high concentrations of old cars. 州和地方机构应该将有限的推广和教育资金用于旧车密集地区的家庭，而零排放汽车的普及程度却很低.

• 提供超越私人乘用车的交通解决方案. 尽管加州试图减少车辆行驶里程, 它继续投资于优先考虑汽车拥有率的汽车激励计划. Agencies should consider further funds for programs that promote alternative modes of transportation, 比如公共交通, 走, 汽车共享, 和(e -)骑自行车.

• Evaluate and adjust incentive programs based on changing conditions in the electric vehicle (EV) market. 尽管电动汽车价格不断下降, the pandemic's impact on the supply of EVs has created barriers to the purchase of both new and used EVs. 加州应该继续评估和调整其激励计划，以根据人们的需求最好地帮助他们. While a complete switch to zero-emissions technology will happen in the longer term, the prices and limited supply of electric vehicles can make their purchases more difficult in the near term. 因此, the state should not discourage drivers from switching to other types of cleaner and cheaper-to-fuel vehicles, 即使不是零排放.

结论

为所有加州人创造一个更清洁、更安全的交通未来是可能的. To realize it, the state must commit to retiring the dirtiest vehicles on the road. 通过持续投资和有针对性的政策, 加州可以保护其脆弱的社区免受有害的空气污染, 节省金钱和生命.

尾注

¹We excluded vehicles older than 1976; our input sources lacked detailed data on vehicles manufactured before 1976. 数据集中最新的车辆是2021年的车型.

² 这份报告使用拉丁裔这个词来描述对美国人口普查问题“这个人是西班牙裔吗?”回答“是”的人, 拉丁美洲人, 或者西班牙血统?人口普查在一个单独的问题中收集了种族数据. 白人这个词描述的是对西班牙人说“不”的人, 拉丁美洲人, or Spanish ethnicity question and choosing the response "White回答“这个人是什么种族??“黑人”一词描述的是对西班牙人说“不”的人, 拉丁美洲人, 或者西班牙问题，然后选择“黑人还是非洲人”.回答“这个人是什么种族??"

³ Maps showing 污染 concentration and vehicle distribution are available online at http://blog.spreadcrushers.com/dave-reichmuth/cleaner-cars-cleaner-air.

这是该报告的浓缩在线版本. 有关所有数据、参考文献和全文，请下载报告全文 PDF.