更清洁的汽车，更清洁的空气

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由于道路上的交通污染，加州的空气质量一直很差. 早在1966年, 该州的617888九五至尊娱乐, 地理位置, and large number of vehicles led California to initiate regulatory action to reduce 污染 from passenger cars and trucks. 由于监管方面的持续进展, the air-polluting emissions of new passenger vehicles currently for sale are much lower than those of older vehicles.

汽油车的排放直接或间接地产生细颗粒物, 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. Chronic exposure in pregnancy and childhood has also been linked to slowed lung-function growth and the development of asthma, 对健康的其他负面影响.

加州道路上的一小部分车辆，旧车和卡车比新车污染更严重

从2004年开始, California implemented updated Low-Emission Vehicle (LEVII) tailpipe 污染 standards for passenger vehicles that required significant reductions in air 污染 emissions. Older vehicles (pre-2004) make up 19 percent of the state's passenger vehicles and only 12 percent of miles driven, yet they emit almost three times as much smog-forming nitrogen oxides 污染 as all 2004 and later vehicles combined. They are responsible for 73 percent of all nitrogen oxides exhaust from passenger vehicles and 64 percent of reactive organic gases (Table 1). 这些污染物可以在大气中反应形成有害的PM_2.5 污染.

尽管在加州道路上行驶的车辆中，老旧车辆只占不到五分之一, 它们产生的氮氧化物和活性有机气体排放量比所有新型汽车的总和还要多.

旧车排放的有害空气污染分布不均

使用InMAP空气质量模型和来自加州空气资源委员会的数据, the Union of Concerned Scientists (UCS) and The Greenlining Institute (Greenlining) estimated the formation and transport of PM_2.5 污染 from the use of older passenger vehicles (defined as model year 1976 through 2003) and newer ones (model year 2004 through 2021).¹ 结合PM_2.5 污染物浓度与美国人口普查数据, 我们估计了加州人暴露在旧车造成的有害空气污染中的情况.

我们的分析表明PM_2.5 exposure from the use of pre-2004 vehicles is inequitably distributed across racial and demographic groups in California. 所有暴露于PM最高的区域_2.5 老旧车辆的车辆分布在加州南部，主要集中在洛杉矶中部. PM污染负担最重的社区_2.5 from older vehicles---more than twice the state average---have a higher percentage of low- and moderate-income households than areas unburdened by air 污染 from these vehicles.

在该州颗粒物暴露率最高的地区 _2.5 由于老旧车辆造成的污染，超过一半的家庭年收入低于6万美元. 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. 收入较高的家庭也较少接触到旧车造成的污染.

我们还发现了乘用车空气污染暴露的种族和民族差异. 这些差异在老旧车辆的污染上也比整个车队的污染更大. 与所有乘用车和卡车相比，白人接触到的PM浓度低17%_2.5 低于州平均水平, while 拉丁美洲人 Californians are exposed to 13 percent higher concentrations and Black Californians are exposed to 11 percent higher concentrations.²

只看旧车的污染情况, 加州白人接触到的PM浓度平均要低20% _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 from older vehicles---greater than twice the state average---are home to much higher proportions of Black and 拉丁美洲人 people than the state as a whole. 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, Californians who already face the worst exposure to 污染 from all sources also face the brunt of emissions from older vehicles. 增加接触PM _2.5 旧车污染与社区在CalEnviroScreen上的得分相关.0, a screening methodology that helps identify communities that are disproportionately burdened by multiple sources of 污染. CalEnviroScreen中得分最高(负担最重)的人口普查区的人.0 are exposed to twice the concentration of 污染 from older vehicles as are those in the lowest-scoring census tracts.

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. 一种方案只考虑冷启动排放，并假设这些排放发生在车辆注册的地方. 第二种情况假设所有尾气排放都发生在车辆注册的地方. 我们估计，旧车排放导致每年97到421人过早死亡. 影响主要集中在南加州，尤其是洛杉矶县.

农村地区旧车的比例更高

While Southern California's urban areas have the most older vehicles (and highest exposure to the resulting 污染), 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, it is imperative that California agencies administering incentive programs for retiring and replacing vehicles prioritize getting the oldest cars off the state's roads. 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. This will help the state identify approaches to reducing the inequitable distribution of this 污染 from older passenger vehicles.

UCS和Greenlining建议对州政策和计划进行以下更改:

• 优先向拥有旧车的重点人群提供奖励. 州政府机构应该对现有的激励方案进行计划性改革, 比如清洁汽车4和清洁汽车援助计划, 优先投资于旧车高度集中的低收入和弱势社区.

• 在旧车高度集中的地区进行有意的、有针对性的推广和教育. State and local agencies should target their limited outreach and education funds to households in areas with high concentrations of old cars and limited uptake of zero-emissions vehicles.

• 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. 各机构应考虑进一步为促进替代交通方式的项目提供资金, 比如公共交通, 走, 汽车共享, 和(e -)骑自行车.

• 根据电动汽车市场的变化评估和调整激励方案. 尽管电动汽车价格不断下降, 新冠肺炎疫情对电动汽车供应的影响为购买新电动汽车和二手电动汽车制造了障碍. California should continue to evaluate and adapt its incentive programs to best assist people based on their needs. 而从长远来看，完全转向零排放技术将会发生, 电动汽车的价格和有限的供应可能会使他们在短期内更难购买. 因此, 国家不应该阻止司机转向其他类型的更清洁、更便宜的燃料汽车, 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. 为了实现这一目标，该州必须承诺淘汰道路上污染最严重的车辆. 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 This report uses the term 拉丁美洲人 to describe persons answering "yes" to the US Census question "Is this person of Hispanic, 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, 或者西班牙种族问题，在回答“这个人是什么种族”时选择“白人”?“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 有关污染浓度及车辆分布的地图，可于 http://blog.promisesurfing.net/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.