Spatiotemporal Evolution, Regional Differentiation, and National Day Air-Quality Patterns at China’s 5A Tourist Attractions, 2000–2024

Imagine standing at the edge of a vast, ancient forest or atop a misty mountain peak, waiting for the view to clear. For travelers, the quality of the air is not just a background detail; it is part of the experience itself. When the sky is hazy, the landscape fades, and the sense of health and well-being that comes with being outdoors can vanish. This is especially true for the most famous scenic spots in China, known as 5A attractions. These are the country's premier destinations, drawing millions of visitors who expect the best natural beauty. But for years, scientists and planners have struggled to answer a simple question: what has the air been like at these specific places over the last two decades? While we know that cities have seen changes in air quality, the air surrounding a remote temple, a lake, or a canyon often tells a different story, one that gets lost when we only look at broad city averages.

To understand this story, researchers needed a way to look at the air not just as a single number, but as a pattern of days. They focused on tiny particles suspended in the air, known as PM2.5, which are small enough to be breathed deep into the lungs and are a key measure of pollution. Instead of just calculating an average for a whole year, which can hide the fact that a year might have been mostly clean with a few terrible smoggy weeks, this study looked at the share of days that were excellent, good, or polluted. By using a high-resolution map of air quality that covers the entire country, the researchers could trace the history of the air at 258 specific tourist sites from the year 2000 through 2024. They treated these locations as fixed points, asking how the air quality at these exact spots has changed over time, regardless of whether the sites were officially rated as top-tier in every single year of that period.

The results reveal a dramatic transformation in the air we breathe at these destinations. In the early 2000s, the air at many of these famous spots was frequently hazy. By 2013, the situation had actually worsened in some ways, with a large portion of these sites experiencing polluted air on more than a quarter of the days. However, a sharp turning point arrived in the mid-2010s. Since then, the pattern has shifted decisively. By 2024, the air at these locations had become remarkably clean. The study found that 86 percent of the attractions now enjoy excellent air quality on more than 60 percent of the days. Even more striking, nearly 70 percent of these sites have excellent air on more than 70 percent of the days, and for 18 percent of them, the air is excellent on more than 90 percent of the days. The number of days with heavy pollution has dropped so low that for most sites, it is now a rare event, occurring on less than 10 percent of the days, and for many, it has effectively disappeared.

This improvement, however, is not spread out evenly across the country. The researchers divided the sites into six major regions and found that while every region is getting cleaner, they are getting there at different speeds and with different results. The Southwest region emerged as the clear leader, with 35 percent of its attractions enjoying excellent air on more than 90 percent of the days in 2024. In contrast, the North region, which includes many of the country's most populous and industrial areas, showed strong improvement but still lagged behind. In the North, only about 8 percent of the sites reached that high 90-percent threshold for excellent days. The Northwest region also retained a slightly higher burden of pollution compared to the rest of the country, though it too has seen significant gains. This tells us that while the national picture is one of vast improvement, the experience of a traveler in the Southwest is currently different from that of a traveler in the North.

The study also looked specifically at the National Day holiday, a week-long period in early October when millions of people travel. This period is critical because it tests whether clean air is just a fleeting occurrence or a stable condition. The researchers found that having a single day of excellent air is different from having seven days in a row. In 2024, the stability of the air varied wildly by region. In the Northeast, East, and Southwest, nearly all the sites managed to keep the air excellent for the entire seven-day holiday. In the North, however, while the air was often good on any given day, only about 8 percent of the sites managed to stay excellent for the full week. This distinction is vital for travelers and managers: it shows that even in a generally clean region, the holiday period can still bring variability that disrupts the perfect travel experience.

It is important to understand what this study does and does not say. The researchers did not try to prove that tourism itself caused the air to get better or worse, nor did they calculate how much cleaner air has boosted visitor numbers. They also did not determine exactly why some regions are cleaner than others, whether it is due to local factories, wind patterns, or geography. Instead, they provided a clear, descriptive map of what has happened. They showed that the air at China's most famous tourist spots has undergone a structural shift from a mix of good and bad days to a state where excellent days are the norm. This shift happened broadly across the country, but the journey to perfect stability is still ongoing in some areas. For the curious traveler or the concerned observer, the takeaway is clear: the skies over China's greatest natural and cultural treasures are significantly clearer than they were a generation ago, offering a much better view for the millions who come to see them.