[ti:How to Reduce Risks of Bad Air Quality]
[al:Health & Lifestyle]
[ar:VOA]
[dt:2025-02-27]
[by:www.voase.cn]
[00:00.00]Air quality differs from place to place and day to day. 
[00:06.84]But about 99 percent of the world's population breathes air at some point that does not meet pollution guidelines set by the World Health Organization (WHO).
[00:23.36]Different forms of air pollution kill about 7 million people each year, the U.N. health agency estimates.
[00:34.56]But health experts say there are some actions individuals can take to protect themselves, even in the world's most polluted cities.
[00:47.23]The first step is to start with the understanding that air is not only polluted when it looks smoky or smoggy, said Tanushree Ganguly.
[01:00.01]She is an air quality expert with the Energy Policy Institute of Chicago's India program.
[01:09.05]"Blue skies can't guarantee you clean air," Ganguly told The Associated Press.
[01:16.68]Air pollutants often come from people burning things.
[01:22.84]Examples include fuels as well as clearing operations involving crops or trees. 
[01:32.22]Pollutants can also be released from wildfires.
[01:37.38]Among the most dangerous particles we can breathe in are called particulate matter.
[01:45.71]The smallest of these are known as PM 2.5.
[01:51.81]This is because they are less than 2.5 microns in diameter.
[01:59.24]These particles can travel deep inside human lungs and are mostly created by burning fuels.
[02:09.63]Larger particles, known as PM 10, are linked to agriculture, roadways, mining or wind-blown dust.
[02:22.08]Other dangerous pollutants include gases like nitrogen dioxide or sulfur dioxide, which are also produced from burning fuels. 
[02:35.41]This information comes from Anumita Roychowdhury, an air pollution expert at the Center for Science and Environment in New Delhi.
[02:48.75]The American-based Health Effects Institute says air pollution is the second-largest risk factor for early death worldwide, behind high blood pressure.
[03:02.04]Short-term exposure can cause asthma attacks and increase the risk of heart attacks and stroke, especially in older people and those with existing medical problems.
[03:17.98]Long-term exposure can cause serious heart and lung problems that can lead to death.
[03:26.07]A recent study by the U.N. children's agency UNICEF found that more than 500 million children in East Asia and Pacific countries breathe unhealthy air.
[03:41.52]The pollution is linked to the deaths of 100 children under age 5 every day. 
[03:49.96]June Kunugi, UNICEF's Regional Director for East Asia, said the polluted air limits growth, harms lungs and affects thinking abilities.
[04:03.26]"Every breath matters, but for too many children every breath can bring harm," she said.
[04:11.12]Over 6,000 cities in 117 countries now record and follow air quality levels.
[04:22.76]Many mobile apps include air quality information as well. 
[04:27.88]But it can be difficult to know how bad the air is by looking at these numbers.
[04:36.50]To help people better understand air quality levels, many countries have established an air quality index, or AQI.
[04:50.21]Larger numbers on this index mean worse air.
[04:56.22]Different countries have different air quality standards.
[05:02.64]For example, India's daily PM 2.5 limit is more than 1.5 times higher than in Thailand and 4 times higher than WHO standards.
[05:19.97]For individuals, experts say the goal should be to limit exposure when air quality is bad, by staying indoors or wearing a mask.
[05:33.45]This is not always possible, though. 
[05:37.47]Danny Djarum is with the World Resources Institute.
[05:41.47]He told the AP there are many people who live or work outside and "can't really afford" to stay indoors.
[05:51.49]People also need to watch indoor air pollution that can be caused by common household activities like cooking or burning incense.
[06:03.85]While air purifiers can help reduce indoor air pollution, experts say they do have limitations.
[06:13.72]The devices work by pulling air from a room and then pushing it through a filter that traps pollutants.
[06:22.82]The filtered air is then sent back into the room.
[06:27.04]Air purifiers work best when used in small spaces and when people are nearby. 
[06:35.44]This is because they can only clean a certain amount of air, said Rajasekhar Balasubramanian of the National University of Singapore. 
[06:48.28]He added, "If we have a tiny air purifier in a large room, it won't be effective."
[06:56.15]I'm John Russell.
[06:58.63]And I'm Caty Weaver.