Researchers, including those from Johns Hopkins University in the US, noted that children had one extra day when they suffered with asthma symptoms for every 305 metres between their home and the park.
For example, a child who lives next to a park had an average of five symptomatic days and a child living 305 metres from the park had six symptomatic days, they said.
Among older children, those living next to the park had an average of five symptomatic days, whereas a child living only 152 metres from the park had six symptomatic days, researchers said.
"The effect looks strongest for children aged six years and older. This might be because they have more freedom to choose where they want to go compared to younger children," DePriest said.
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Researchers looked at inner-city children with persistent asthma and compared the number of days they suffered with symptoms over a period of two weeks with the distance from their homes to the nearest park.
Researchers asked parents how many days each child had suffered with symptoms such as being short of breath, chest pain and wheezing.
At the same time, they mapped the distances between the children's home addresses and the closest green space.