Frequently Asked Questions
About Air Quality
Q: What does “WHO threshold” mean?
A: The World Health Organization has published “Air quality guidelines” (see latest update in 2021), establishing safe levels for air pollutants based on extensive health research. When air quality falls below these levels, there’s an increased health risk.
Q: Why do I see two different scores for pollution?
A: Health impacts differ between short-term exposure (acute effects during bad days) and long-term exposure (cumulative effects). Both matter, but for different reasons.
Q: How are “pollution days” counted?
A: A day is counted as a pollution day when the peak pollution level exceeds the WHO threshold for at least one of the six considered pollutants (NO2, O3, PM2.5 and PM10), at any point during that day, even if it only occurs for part of the day. This conservative approach ensures you’re aware of all potentially concerning exposure periods.
Q: Is a “C” score bad?
A: A “C” score indicates average quality with moderate pollution episodes. While not ideal, it’s better than D or E. Consider your personal health situation when interpreting - sensitive individuals may want to aim for B or better.
About Accessibility & Ecomobility
Q: Why are distances “straight-line”?
A: Straight-line (Euclidean) distance provides a consistent and comparable measure. Actual travel time depends on road networks, traffic, and transport schedules.
Q: Is 5 km to a train station far?
A: It depends on local context. In urban areas, 5 km might be a 15-minute drive or 30-minute bike ride. In rural areas, it might represent good accessibility.
Q: Why might my ecomobility score be low even with bus stops nearby?
A: The score also considers cycling infrastructure and metro access. A few bus stops alone may not be sufficient for a high score.
Q: Does the score account for service frequency?
A: No. The score measures infrastructure presence, not service quality or frequency. A bus line with one trip per day counts the same as one with trips every 10 minutes.
Q: Why don’t I see all infrastructure on the map?
A: For map performance, some features may be sampled in very dense areas. The calculations use all available data, but the visualization may show a representative sample.
About Weather Comfort
Q: What does “average temperature” mean?
A: Typical temperature you can expect for that season, based on the last 5 years.
Q: What counts as a “rainy day”?
A: A day with more than 1 mm of precipitation.
Q: How is a “sunny day” defined?
A: A day with strong solar radiation indicating clear to mostly clear skies.
Q: Why is the heat island percentage sometimes high?
A: If you live in an urban center, a high percentage is normal. The measurement covers a small area (1 km radius).
Q: What if no heat islands are detected?
A: Good news! Your area has good vegetation coverage or lower building density.
About Water Stress
Q: What causes high water stress?
A: Water stress occurs when water demand (from households, agriculture, industry) exceeds sustainable supply from rivers, lakes, and groundwater. Climate, population density, and economic activity all play roles.
Q: Is 50% water stress bad?
A: Water stress above 40% is considered “high” and indicates significant pressure on water resources. Values above 80% indicate “extremely high” stress with severe scarcity concerns.
Q: Can water stress change quickly?
A: The underlying data reflects 2019 estimates based on long-term patterns (1979-2019). While seasonal variations occur within the year, major changes typically happen over years or decades due to climate shifts, infrastructure changes, or population growth.
Q: How current is the water stress data?
A: The water stress baseline reflects 2019 conditions based on 40 years of historical data (1979-2019). While not real-time, it provides a robust assessment of typical watershed-level conditions.
About Vegetation Health
Q: What’s a “good” vegetation health percentage?
A: Generally, values above 70% indicate healthy, thriving vegetation relative to historical conditions. Values of 40-70% are moderate, and below 40% suggests stressed vegetation that may lack water or face other environmental challenges.
Q: Why does vegetation health matter for water?
A: Healthy vegetation indicates adequate water availability. Declining vegetation health can signal developing drought conditions or water scarcity before it becomes critical.
Q: Can vegetation health be poor in winter?
A: The index accounts for seasonal patterns by comparing current conditions to the historical (2020-2023) range for the same time of year. Low values in winter would indicate the vegetation is unhealthy relative to typical winter conditions, not just naturally dormant.
Q: Why might plant species count be low in my urban area?
A: Urban areas genuinely have fewer plant species due to development. Additionally, scientific observations are often concentrated in natural areas, so city counts may be underestimated.
Q: What if I know there’s more vegetation than the map shows?
A: The coverage data is from 2021 satellite imagery at 10-meter resolution. Recent plantings or changes won’t be reflected. Small gardens or individual trees may also not be captured. The density map shows summer conditions only.
About Biodiversity
Q: What counts as a “threatened species”?
A: Species classified by the International Union for Conservation of Nature (IUCN) as Vulnerable, Endangered, Critically Endangered, or Near Threatened. These are species facing various levels of extinction risk.
Q: Is it bad if threatened species are in my area?
A: Not necessarily. It means your area contains important habitat. However, it also signals these species need protection and their habitat should be preserved.
Q: Why might my biodiversity score be lower in the city?
A: Urban areas naturally have less habitat diversity due to buildings and infrastructure. However, parks, gardens, and green corridors can still support surprising biodiversity even in cities.
Q: The species count seems low - are there really so few species?
A: The count reflects observed and recorded species from scientific databases. Many species may be present but not yet documented, especially in less-studied urban areas.
About Landscape
Q: What makes a landscape score “good”?
A: Higher scores reflect more natural areas - especially tree cover, water bodies, and wetlands - and less built-up space. These areas offer both aesthetic beauty and ecosystem benefits.
Q: Can my landscape score change?
A: The score is based on 2021 satellite data, so recent changes (new parks, developments) aren’t yet reflected. Over time, vegetation or development would affect future scores.
About the 3-30-300 Rule
Q: I can see trees but the report says “No” - why?
A: The analysis uses satellite imagery to detect tree canopy at your specific address point. Small trees, trees partially blocked by buildings, or trees just outside the detection area may not register.
Q: What size trees count for the “Rule of 3”?
A: Any trees with sufficient canopy to be visible from satellite imagery. This typically means established trees, not recently planted saplings.
Q: The park measurement seems wrong - there’s a park nearby!
A: The analysis looks for green spaces larger than 5,000 m² (roughly half a hectare). Small neighborhood gardens or pocket parks below this threshold aren’t counted, though they still provide benefits.