尾氣

尾氣是指車輛內的燃料（如天然氣、汽油、柴油、重油、生物柴油混合物^[1]或煤）經過燃燒而排放出來的氣體。根據車輛發動機的類型，尾氣通過排氣管等不同的方式排放到大氣中。

機動車排放尾氣會導致空氣污染，並且是一些大城市產生煙霧的主要因素。根據麻省理工學院2013年的一項研究表明，僅在美國，每年就有53,000人因汽車尾氣排放而過早死亡。^[2]根據同一所大學的另一項研究，在英國，僅尾氣造成的交通煙霧每年就會導致5,000人死亡。^[3]

客車排放統計

美國環保局估算客車平均排放量，2000年7月^[4]
成分	排放率	年污染排放
碳氫化合物	2.80 克/英里 (1.75 克/公里)	77.1英磅（35.0公斤）
一氧化碳	20.9 克/英里 (13.06 克/公里)	575英磅（261公斤）
NO_x	1.39 克/英里 (0.87 克/公里)	38.2英磅（17.3公斤）
二氧化碳——溫室氣體	0.916英磅每英里（258克每公里）	11,450英磅（5,190公斤）

美國輕型汽車、輕型卡車，中型汽車—— 2級排放標準^[5]
成分	排放率	年污染排放
NMOG (揮發性有機物)	0.075 克/英里 (0.046 克/公里)	2.1英磅（0.95公斤）
一氧化碳	3.4 克/英里 (2.1 克/公里)	94英磅（43公斤）
NO_X	0.05 克/英里 (0.0305 克/公里)	1.4英磅（0.64公斤）
甲醛	0.015 克/英里 (0.0092 克/公里)	0.41英磅（0.19公斤）

火花點火發動機

火花點火發動機中：

成分	汽油	柴油
內燃機尾氣^[7] ^{所有數據皆為估算}	% of total
氮	71	67
一氧化碳	14	12
水蒸氣	12	11
氧氣		10
微量元素^{[來源請求]}	< 0.5	~ 0.3
一氧化氮	< 0.25	< 0.15
一氧化碳	1 - 2	< 0.045
顆粒物		< 0.045
烴	< 0.25	< 0.03
二氧化硫	些許痕跡	< 0.03

引述

^ Omidvarborna; et al. Characterization of particulate matter emitted from transit buses fueled with B20 in idle modes. Journal of Environmental Chemical Engineering. 2014, 2 (4): 2335–2342. doi:10.1016/j.jece.2014.09.020.
^ Caiazzo, Fabio; Ashok, Akshay; Waitz, Ian A.; Yim, Steve H.L.; Barrett, Steven R.H. Air pollution and early deaths in the United States. Part I: Quantifying the impact of major sectors in 2005. Atmospheric Environment. November 2013, 79: 198–208. Bibcode:2013AtmEn..79..198C. doi:10.1016/j.atmosenv.2013.05.081.
^ Roland Pease. Traffic pollution kills 5,000 a year in UK, says study. BBC News. [2021-07-24]. （原始內容存檔於2018-09-03）.
^ Average Annual Emissions and Fuel Consumption for Passenger Cars and Light Trucks (PDF). Transportation and Air Quality. United States Environmental Protection Agency. [2015-04-18]. （原始內容存檔 (PDF)於2015-06-17）.
^ Light-Duty Vehicle, Light-Duty Truck, and Medium-Duty Passenger Vehicle -- Tier 2 Exhaust Emission Standards. Emission Standards Reference Guide. United States Environmental Protection Agency. 14 November 2012 [2015-04-18]. （原始內容存檔於2015-02-26）.
^ State and County Emission Summaries: Volatile Organic Compounds. Air emission sources. United States Environmental Protection Agency. 25 October 2013 [2015-04-18]. （原始內容存檔於2015-04-16）.
^ Self-Study Programme 230: Motor Vehicle Exhaust Emissions (PDF). AUDI. April 2000 [23 March 2012]. （原始內容存檔 (PDF)於2015-08-07）.

外部連結

Health and Air Pollution （頁面存檔備份，存於網際網路檔案館） Publication of the California Air Resources Board
The Encyclopedia Of Filters - Dust Collection （頁面存檔備份，存於網際網路檔案館） An overview of the science of dust collection systems, including those used for pollution control.
Cone, Tracie. California Air Pollution Kills More People Than Car Crashes, Study Shows. Huffington Post. 13 November 2008 [2015-04-18]. （原始內容存檔於2015-01-01）.
Automotive Exhaust Chemicals: disease causing effects. Alpha Online. Environmed Research Inc. （原始內容存檔於2014-07-05）.
Cars, Trucks, and Air Pollution. Clean Vehicles. Union of Concerned Scientists. 3 September 2013 [2015-04-18]. （原始內容存檔於2012-05-07）.
General Information - Emissions and ADR's. Australian Government, Department of Infrastructure and Regional Development. （原始內容存檔於2015-01-01）.
Environment, Health & Transportation: Motor Vehicles and Air Pollution. International Bicycle Fund. [25 October 2013]. （原始內容存檔於2015-03-21）.
Chevron Motor Gasoline Technical Review
Chevron Diesel Fuels Technical Review

柴油尾氣：

[sciencedirect.com-1] Omidvarborna; et al. Characterization of particulate matter emitted from transit buses fueled with B20 in idle modes. Journal of Environmental Chemical Engineering. 2014, 2 (4): 2335–2342. doi:10.1016/j.jece.2014.09.020.

[2] Caiazzo, Fabio; Ashok, Akshay; Waitz, Ian A.; Yim, Steve H.L.; Barrett, Steven R.H. Air pollution and early deaths in the United States. Part I: Quantifying the impact of major sectors in 2005. Atmospheric Environment. November 2013, 79: 198–208. Bibcode:2013AtmEn..79..198C. doi:10.1016/j.atmosenv.2013.05.081.

[3] Roland Pease. Traffic pollution kills 5,000 a year in UK, says study. BBC News. [2021-07-24]. （原始內容存檔於2018-09-03）.

[4] Average Annual Emissions and Fuel Consumption for Passenger Cars and Light Trucks (PDF). Transportation and Air Quality. United States Environmental Protection Agency. [2015-04-18]. （原始內容存檔 (PDF)於2015-06-17）.

[5] Light-Duty Vehicle, Light-Duty Truck, and Medium-Duty Passenger Vehicle -- Tier 2 Exhaust Emission Standards. Emission Standards Reference Guide. United States Environmental Protection Agency. 14 November 2012 [2015-04-18]. （原始內容存檔於2015-02-26）.

[epa.gov-6] State and County Emission Summaries: Volatile Organic Compounds. Air emission sources. United States Environmental Protection Agency. 25 October 2013 [2015-04-18]. （原始內容存檔於2015-04-16）.

[AUDIEmiss1-7] Self-Study Programme 230: Motor Vehicle Exhaust Emissions (PDF). AUDI. April 2000 [23 March 2012]. （原始內容存檔 (PDF)於2015-08-07）.

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