The top 500 cities by pm2.5 annual mean concentration năm 2024

The AirData Air Quality Index Summary Report displays an annual summary of Air Quality Index (AQI) values for counties or core based statistical areas (CBSA). Air Quality Index is an indicator of overall air quality, because it takes into account all of the criteria air pollutants measured within a geographic area. Although AQI includes all available pollutant measurements, you should be aware that many areas have monitoring stations for some, but not all, of the pollutants. Each row of the AQI Report lists summary values for one year for one county or CBSA. The summary values include both qualitative measures (days of the year having "good" air quality, for example) and descriptive statistics (median AQI value, for example).

Summary statistics for the current year are incomplete because data are still being reported and quality assured. Data for the current year are considered preliminary until May 1 of the following year. Therefore, comparing reported values for the current year with previous years may not be valid.

How can I sort the report?

You can sort the report by clicking on any column heading. The first time you click on a column, it will sort in ascending order. If you click again, it will sort in descending order.

What do the report columns mean?

# Days with AQI Number of days in the year having an Air Quality Index value. This is the number of days on which measurements from any monitoring site in the county or MSA were reported to the AQS database.

# Days Good Number of days in the year having an AQI value 0 through 50.

# Days Moderate Number of days in the year having and AQI value 51 through 100.

# Days Unhealthy for Sensitive Groups Number of days in the year having an AQI value 101 through 150.

# Days Unhealthy Number of days in the year having an AQI value 151 through 200.

# Days Very Unhealthy Number of days in the year having an AQI value 201 through 300.

# Days Hazardous Number of days in the year having an AQI value 301 or higher. Note: The official AQI hazardous category range is 301-500. Values above 500 are considered “Beyond the AQI” and are included in the # Days Hazardous in this report.

AQI Max The highest daily AQI value in the year.

AQI 90th %ile 90 percent of daily AQI values during the year were less than or equal to the 90th percentile value.

AQI Median Half of daily AQI values during the year were less than or equal to the median value, and half equaled or exceeded it.

# Days CO # Days NO2 # Days O3 # Days PM2.5 # Days PM10 A daily index value is calculated for each air pollutant measured. The highest of those index values is the AQI value, and the pollutant responsible for the highest index value is the "Main Pollutant." These columns give the number of days each pollutant measured was the main pollutant. A blank column indicates a pollutant not measured in the county or CBSA.

Note: As of Dec 8, 2021, SO2 is no longer included in this report because SO2 concentrations tend to be very localized and not necessarily representative of broad geographical areas like counties and CBSAs. SO2 concentrations (and corresponding AQI values) are available at the monitor level via other AirData tools that provide monitor level data.

Air quality in most cities worldwide that monitor outdoor (ambient) air pollution fails to meet WHO guidelines for safe levels, putting people at additional risk of respiratory disease and other health problems.

WHO’s urban air quality database covers 1600 cities across 91 countries – 500 more cities than the previous database (2011), revealing that more cities worldwide are monitoring outdoor air quality, reflecting growing recognition of air pollution’s health risks.

Only 12% of the people living in cities reporting on air quality reside in cities where this complies with WHO air quality guideline levels. About half of the urban population being monitored is exposed to air pollution that is at least 2.5 times higher than the levels WHO recommends - putting those people at additional risk of serious, long-term health problems.

In most cities where there is enough data to compare the situation today with previous years, air pollution is getting worse. Many factors contribute to this increase, including reliance on fossil fuels such as coal fired power plants, dependence on private transport motor vehicles, inefficient use of energy in buildings, and the use of biomass for cooking and heating.

But some cities are making notable improvements - demonstrating that air quality can be improved by implementing policy measures such as banning the use of coal for “space heating” in buildings, using renewable or “clean” fuels for electricity production, and improving efficiency of motor vehicle engines.

Health risks caused by air pollution

The latest available data have prompted WHO to call for greater awareness of health risks caused by air pollution, implementation of effective air pollution mitigation policies; and close monitoring of the situation in cities worldwide.

“Too many urban centres today are so enveloped in dirty air that their skylines are invisible,” said Dr Flavia Bustreo, WHO Assistant Director-General for Family, Children and Women's Health. “Not surprisingly, this air is dangerous to breathe. So a growing number of cities and communities worldwide are striving to better meet the needs of their residents - in particular children and the elderly."

In April 2014, WHO issued new information estimating that outdoor air pollution was responsible for the deaths of some 3.7 million people under the age of 60 in 2012. The Organization also emphasised that indoor and outdoor air pollution combined are among the largest risks to health worldwide.

There are many components of air pollution, both gaseous and solid. But high concentrations of small and fine particulate pollution is particularly associated with high numbers of deaths from heart disease and stroke, as well as respiratory illnesses and cancers. Measurement of fine particulate matter of 2.5 micrometers or less in diameter (PM2.5) is considered to be the best indicator of the level of health risks from air pollution.

In high-income countries, 816 cities reported on PM2.5 levels with another 544 cities reporting on PM10, from which estimates of PM2.5 can be derived. In low- and middle-income countries, however, annual mean PM2.5 measurements could be accessed in only 70 cities; another 512 cities reported on PM10 measurements.

Measures to clean air

“We can win the fight against air pollution and reduce the number of people suffering from respiratory and heart disease, as well as lung cancer,” said Dr Maria Neira, WHO Director for Public Health, Environmental and Social Determinants of Health. “Effective policies and strategies are well understood, but they need to be implemented at sufficient scale. Cities such as Copenhagen and Bogotà, for example, have improved air quality by promoting ‘active transport’ and prioritizing dedicated networks of urban public transport, walking and cycling.”

The report notes that individual cities can take local action to improve air quality and thus go against regional trends. And good air quality can go hand in hand with economic development, as indicated by some major cities in Latin America which meet, or approach, the WHO air quality guidelines.

“We cannot buy clean air in a bottle, but cities can adopt measures that will clean the air and save the lives of their people,” said Dr Carlos Dora, Coordinator, Interventions for Healthy Environments, WHO Department of Public Health, Environmental and Social Determinants of Health.

Measures include ensuring that houses are energy efficient, that urban development is compact and well served by public transport routes, that street design is appealing and safe for pedestrians and cyclists, and waste is well managed. Such activities not only clean the air but can also serve as a catalyst for local economic development and the promotion of healthy urban lifestyles.

Despite the upswing in air quality monitoring, many cities in low and middle income countries still lack capacity to do so. There is a particular shortage of data in WHO’s Africa and Eastern Mediterranean regions.

The release of today’s data is a significant step in WHO’s ongoing work to advance a roadmap for preventing diseases related to air pollution. This involves the development of a global platform on air quality and health to generate better data on air pollution-related diseases and strengthened support to countries and cities through guidance, information and evidence about the health gains associated with different activities.

Notes to editors:

Primary source of data has been compiled from official national/sub-national reports, national/ sub-national web sites containing measurements of PM10 or PM2.5, and relevant national agencies. Measurements reported by the following regional networks were used: the Asian Clean Air Initiative for Asia, and Airbase for Europe. In the absence of data from the previous sources, data from: (a) UN agencies; (b) Development agencies; and (c) articles from peer reviewed journals were used.

Annual mean concentrations of particulate matter (PM10 and/or PM2.5) based on daily measurements, or data which could be aggregated into annual means, were included in the database. In the absence of annual means, measurements covering a more limited period of the year were exceptionally used.

WHO regions

Africa Region

Algeria, Angola, Benin, Botswana, Burkino Faso, Burundi, Cameroon, Cape Verde, Central African Republic, Chad, Comoros, Congo, Côte d’Ivoire, Democratic Republic of the Congo, Equatorial Guinea, Eritrea, Ethiopia, Gabon, Gambia, Ghana, Guinea, Guinea-Bissau, Kenya, Lesotho, Liberia, Madagascar, Malawi, Mali, Mauritania, Mauritius, Mozambique, Namibia, Niger, Nigeria, Rwanda, Sao Tome & Principe, Senegal, Seychelles, Sierra Leone, South Africa, South Sudan, Swaziland, Togo, Uganda, United Republic of Tanzania, Zambia, Zimbabwe

Eastern Mediterranean Region

Afghanistan, Bahrain, Djibouti, Egypt, Iran, Islamic Republic of Iraq, Jordan, Kuwait, Lebanon, Libya, Morocco, Oman, Pakistan, Occupied Palestinian territory, Qatar, Saudi Arabia, Somalia, Sudan, Syrian Arab Republic, Tunisia, United Arab Emirates, Yemen

Which countries have the highest levels of PM2 5?

Most polluted country and region ranking based on annual average PM2.5 concentration (μg/m³).

What are the concentration limits for PM2 5?

The current 24-hour PM2. 5 standard was issued in 2006. o EPA is retaining the existing 24-hour fine particle standard, at 35 µg/m3 . An area meets the 24-hour standard if the 98th percentile of 24-hour PM2. 5 concentrations in one year, averaged over three years, is less than or equal to 35 μg/m3.nullThe National Ambient Air Quality Standards for Particle Pollution - EPAwww.epa.gov › sites › default › files › documents › 2012_aqi_factsheetnull

What is the annual limit for PM2 5?

By reducing air pollution levels, countries can reduce the burden of disease, and long and short-term illnesses. The current guidelines state that annual average concentrations of PM2.5 should not exceed 5 µg/m3, while 24-hour average exposures should not exceed 15 µg/m3 more than 3 - 4 days per year.nullWHO Air Quality Guidelines - C40 Knowledge Hubwww.c40knowledgehub.org › article › WHO-Air-Quality-Guidelinesnull

What major city has the worst air quality?

List of most-polluted cities by particulate matter concentration.